Al toxicity tolarence fi
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Al toxicity , symptoms, tolerance mechanism, genetics of tolerance , developed varieties for Al toxicity..........
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Al toxicity tolarence fi
- 2. MAHESH R HAMPANNAVAR PG14AGR6062 Jnr M.Sc 2Mahesh R Hampannavar
- 3. Contents • Introduction • Al-toxicity symptoms in plants • Site of al accumulation • Injury mechanisms • Genetics of Al Toxicity Resistance • Sources Mineral Toxicity Resistance • Creation of mineral toxicity environment • Selection criteria Al resistance • Characters associated Al toxicity resistance • Al toxicity resistance varieties • conclusion 3Mahesh R Hampannavar
- 4. Introduction • Micro element but not essential element • Al toxicity-soil low pH<5.0 • Free Al ions soluble in low pH • in Acidity soil-Fe,Mn,Al toxicity found • Mn toxicity and deficiency of P,Ca,Mg also interplay in manifestion of Al toxicity 4Mahesh R Hampannavar
- 6. Al-TOXICITY SYMPTOMS IN PLANTS • Poor or stunted growth • Leaf tip death and marginal chlorosis • Deficiency symptoms of Fe,Ca • Effect on leaf area ,chlorophyll content and Hill activity • Stunted and deformed roots- it become stibbier and thicker ,low specific surface • Lateral root thickened and turn brown • Callose formation 6Mahesh R Hampannavar
- 10. SITE OF Al ACCUMALATION • Primary accumalation in Root maristem • At cellular level in cell wall and nucleus • Specific site is cellular membrane of younger and outer root cells 10Mahesh R Hampannavar
- 11. INJURY MECHANISMS Reduced root growth- • Main effect… • Inhibits cell division in root meristem and cell elongatin… • Decrease extensibilityby cross linking protien in middle lamella… • Increase viscocity of protoplasm.. • Inhibition of DNA synthesis… 11Mahesh R Hampannavar
- 12. • Effect of Al-toxicity on nutrient uptake- Ca,Mg,P,Fe and NO¯³ deficiency • Al toxicity affects pollen germination • Chromosomal abnormality and reducesed DNA synthesis • Effect of Al toxicity on cell and cellular components- damaged cytoplasm,disruption of golgi bodies , extesive vacuoleation,cell distortion,cytoplam density 12Mahesh R Hampannavar
- 13. Genetics of Al Toxicity Resistance • Generally polygenic trait • Monogenic in Barley,Maize • MAIZE - Lte2 • BARLEY- Alp 13Mahesh R Hampannavar
- 14. GENETICS OF Al TOXICITY RESISTANCE CROP GENETIC CONTROL HERITABI LITY REMARKS BARLEY Alp -- -- WHEAT 5AL,6A,2DL,4DL,4BL,5D,7D -- -- RYE 3R, 4R,6R -- supressed when intercross with wheat MAIZE Single gene with multiple alleles:pleotropic effect of Lte2 -- Lte2 specifies heat SORGHUM polygenic high Selection would be effective ALFALFA polygenic -- -- 14Mahesh R Hampannavar
- 15. Sources Mineral Toxicity Resistance • Old varieties adopted to acid soil and mineral toxicity • Cultivated varieties bred and cultivated in acid soil region eg- Brazalian wheats 15Mahesh R Hampannavar
- 16. Creation of mineral toxicity environment • Field having mineral toxicity • Pots filled with problem soil • In nutrient solution –based on hydrophonics or sand culture 16Mahesh R Hampannavar
- 20. Selection criteria Al resistance • Shoot dry matter - in pot and nutrient culture • Root length- • Root wieght- In hydrophonics • Root deformation • Root discolouration 20Mahesh R Hampannavar
- 21. • Al exclusion from roots- Eg- In wheat, stained with haematoxylin,donot take up stain are resistance • In field expt- yield is used to measure the resistance , evaluate in normal and stress condition,it suited for parents and F1 21Mahesh R Hampannavar
- 22. Characters associate with Al toxicity resistance • Plant raise pH of their rhizosphere • Al excluded from entering root from mucilage • Al compartmentalized in roots –chelation of organic acid in root • Al accumalation in older leaves eg-tea • Al resistance involve nutritional aspect-NH⁺4, NO⁻3,Ca deficiency,P deficiency 22Mahesh R Hampannavar
- 23. Problems in Al toxicity resistance breeding • Toxicity profile varies with location • Specific Al resistance may not serve the purpose • Al toxicity interact with other mineral Ca,Mg,P so care should be taken during selection • Hydrophonics is expensive and skill required • Double work load- stress and non stresse condition evaluation 23Mahesh R Hampannavar
- 24. Al toxicity resistance varieties • Rice- IR-64, Basmati370,Atlas66,IR-24 • Wheat- BH1146,kedett • Maize- sikuni,B37,C525-M • Sorghum-PaB8A,B37 • Barley-Aura • Soybean-No.62,Lachang • Groundnut-TAG-24,TCGA-5,-6,-10,-34,JL-220 24Mahesh R Hampannavar
- 26. Thank you one and All 26Mahesh R Hampannavar